Police linked 37 suicides last year in Iwate, Miyagi and Fukushima prefectures to the March 2011 disaster, up 13 from a year earlier, with the tally rising progressively each year in Fukushima, the National Police Agency said Thursday.

The figures from the three prefectures hit hardest by the quake and tsunami, with the nuclear crisis compounding the situation in Fukushima, were part of the national suicide tally of 27,283, down 2.1 percent, the fourth straight year of decline, the NPA said.

“The impact of the nuclear accident is prolonging people’s stay in evacuated locations, and this could have affected” the Fukushima figure, an official in the Cabinet Office said.

Fukushima saw the number of suicides increase by 10 to 23. Iwate marked four suicides, down four from a year earlier, while Miyagi had 10 deaths, up seven.

Whether a suicide is linked to the disaster is determined by such factors as the content of a suicide note and statements by relatives, the agency said.

Deaths involving people in evacuation shelters and temporary housing are counted as possible disaster-tied cases. Residents in disaster areas as well as people engaged in restoration work in such areas may also be included.

Of the 23 suicides in Fukushima, 16 involved people who had to evacuate their homes, up five from 2012. This contrasts with four such people in Iwate, up by one. Miyagi recorded no suicides among those who relocated after the disaster.

Yasuyuki Shimizu of the Life Link support center, which works to curb suicides, called for increased measures.

“Many people may be feeling stressed for not knowing when they can go back to their homes, being unable to find transport or feeling isolated from people around them,” he said.

Looking at the total for the three prefectures, health was cited as a cause in 22 suicides. Finances and problems involving daily life were associated with nine cases. Problems with work and family were mentioned in five each.

By age bracket, 12 suicides involved people in their 50s, the largest group, up by seven. Seven were in their 80s or older, up by four.

The nationwide sum stayed below 30,000 for the second year in a row, dropping to 27,283 suicides. Those attributed to finances and daily life issues dropped 11.2 percent. “The economic recovery may have had an impact,” the Cabinet Office official said.

The Health, Labor and Welfare Ministry also releases suicide data as part of population statistics. Those figures may differ from the police agency’s suicide data, which also covers foreign nationals.